Processes for preparing 2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide

ABSTRACT

Provided herein are processes for preparing 2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/945,013, filed Dec. 6, 2019, the disclosure of which is incorporatedherein by reference in its entirety.

FIELD

Provided herein are processes for preparing2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

BACKGROUND

2-(4-Chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamideor a stereoisomer or mixture of stereoisomers, pharmaceuticallyacceptable salt, tautomer, prodrug, solvate, hydrate, co-crystal,clathrate, or polymorph thereof has been shown to have anti-canceractivities. Exemplary formulations of the compound, methods of use andmethods of synthesis of the compound are disclosed in U.S. Pat. Nos.9,499,514 B2; 9,968,596 B2; 9,808,451 B2; 10,052,315 B2; 10,189,808 B2;and 10,245,258 B2; and U.S. Patent Publication Nos. US-2018-0221361-A1;US-2018-0353496-A1; US-2019-0106405-A1 and US-2019-0175573-A1; and U.S.application Ser. No. 16/436,819, filed on Jun. 10, 2019; Ser. No.16/024,581, filed on Jun. 29, 2018; and 62/787,034, filed on Dec. 31,2018, the disclosure of each of which is incorporated herein byreference in its entirety.

There is a need for a more efficient, commercially viable, safe, lesstoxic, and environmentally friendly process for synthesis of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide(Compound 1).

BRIEF SUMMARY

Provided herein are efficient processes for preparing Compound 1. In oneembodiment, provided herein is a process for preparing a polymorph formof Compound 1. In one embodiment, provided herein is a process forpreparing polymorph Form C of Compound 1.

In one embodiment, provided herein is a process for preparing Compound 1comprising contacting an acid salt of3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione with2-(4-chlorophenyl)-2,2-difluoroacetic acid (Compound L1) with2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of thionylchloride (SOCl₂), in a solvent under conditions suitable to provideCompound 1.

In one embodiment, provided herein is a process for preparing Compound1, comprising a step of contacting Compound L

with 2-(4-chlorophenyl)-2,2-difluoroacetic acid under conditionssuitable to provide Compound 1.

In one embodiment, provided herein is a process for preparing CompoundL, comprising contacting Compound G

with a reducing agent and methanesulfonic acid under conditions suitableto provide Compound L

In one embodiment, provided herein is a process for preparing Compound Gcomprising contacting Compound X

wherein L¹ is a leaving group, with 3-aminopiperidine-2,6-dionehydrochloride, under conditions suitable to provide Compound G

In one embodiment, provided herein is a process for preparing CompoundG, comprising contacting Compound D

with 3-aminopiperidine-2,6-dione hydrochloride under conditions suitableto provide Compound G

In one embodiment, provided herein is a process for preparing Compound 1comprising

-   -   a) contacting Compound X

wherein L¹ is a leaving group, with 3-aminopiperidine-2,6-dionehydrochloride under conditions suitable to provide Compound G,

-   -   b) contacting Compound G with a reducing agent and        methanesulfonic acid under conditions suitable to provide        Compound L

-   -   and c) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid under conditions        suitable to provide Compound 1. In one embodiment, L¹ is a        halogen or methanesulfonate. In one embodiment, L¹ is chloro or        methanesulfonate.

In one embodiment, provided herein is a process for preparing Compound 1comprising

-   -   a) contacting Compound D

with 3-aminopiperidine-2,6-dione hydrochloride under conditions suitableto provide Compound G,

-   -   b) contacting Compound G with a reducing agent and        methanesulfonic acid under conditions suitable to provide        Compound L

-   -   and c) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid under conditions        suitable to provide Compound 1.

Further provided herein are chemical intermediates useful in theprocesses provided herein.

Compound 1 is useful in methods of treating cancer. Also disclosed isCompound 1 for use in methods of treating cancer. In one embodiment, thecancer is a solid tumor or a hematological cancer.

These and other aspects of the subject matter described herein willbecome evident upon reference to the following detailed description.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 depicts an XRPD plot of polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

FIG. 2 depicts a SEM image of polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

FIG. 3 depicts a TGA thermogram plot of polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

FIG. 4 depicts a DSC thermogram of polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

FIG. 5 provides a DVS isotherm plot of polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

FIG. 6 provides a ¹H NMR spectrum of polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

FIG. 7 depicts the comparison of the XRPD plots of polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamidebefore and after application of pressure.

DETAILED DESCRIPTION Definitions

Generally, the nomenclature used herein and the laboratory procedures inorganic chemistry, medicinal chemistry, and pharmacology describedherein are those well known and commonly employed in the art. Unlessdefined otherwise, all technical and scientific terms used hereingenerally have the same meaning as commonly understood by one ofordinary skill in the art to which this disclosure belongs. In general,the technical teaching of one embodiment can be combined with thatdisclosed in other embodiments provided herein.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification can mean “one”, butit is also consistent with the meaning of “one or more”, “at least one”and “one or more than one.”

As used herein, the terms “comprising” and “including” can be usedinterchangeably. The terms “comprising” and “including” are to beinterpreted as specifying the presence of the stated features orcomponents as referred to, but does not preclude the presence oraddition of one or more features, or components, or groups thereof.Additionally, the terms “comprising” and “including” are intended toinclude examples encompassed by the term “consisting of”. Consequently,the term “consisting of” can be used in place of the terms “comprising”and “including” to provide for more specific embodiments of theinvention.

The term “consisting of” means that a subject-matter has at least 90%,95%, 97%, 98% or 99% of the stated features or components of which itconsists. In another embodiment the term “consisting of” excludes fromthe scope of any succeeding recitation any other features or components,excepting those that are not essential to the technical effect to beachieved.

As used herein, the term “or” is to be interpreted as an inclusive “or”meaning any one or any combination. Therefore, “A, B or C” means any ofthe following: “A; B; C; A and B; A and C; B and C; A, B and C”. Anexception to this definition will occur only when a combination ofelements, functions, steps or acts are in some way inherently mutuallyexclusive. E.g., “treating, preventing or managing” or similar listingsmeans: “treating; preventing; managing; treating and preventing;treating and managing; preventing and managing; treating, preventing andmanaging”.

The term “Compound 1” refers to“2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide”having the structure:

Unless specifically stated otherwise, where a compound may assumealternative tautomeric, regioisomeric and/or stereoisomeric forms, allalternative isomers are intended to be encompassed within the scope ofthe claimed subject matter. For example, where a compound can have oneof two tautomeric forms, it is intended that both tautomers beencompassed herein.

Thus, the compounds herein may be enantiomerically pure, or bestereoisomeric or diastereomeric mixtures. As used herein and unlessotherwise indicated, the term “stereoisomerically pure” means acomposition that comprises one stereoisomer of a compound and issubstantially free of other stereoisomers of that compound. For example,a stereoisomerically pure composition of a compound having one chiralcenter will be substantially free of the opposite enantiomer of thecompound. A stereoisomerically pure composition of a compound having twochiral centers will be substantially free of other diastereomers of thecompound. A typical stereoisomerically pure compound comprises greaterthan about 80% by weight of one stereoisomer of the compound and lessthan about 20% by weight of other stereoisomers of the compound, morepreferably greater than about 90% by weight of one stereoisomer of thecompound and less than about 10% by weight of the other stereoisomers ofthe compound, even more preferably greater than about 95% by weight ofone stereoisomer of the compound and less than about 5% by weight of theother stereoisomers of the compound, and most preferably greater thanabout 97% by weight of one stereoisomer of the compound and less thanabout 3% by weight of the other stereoisomers of the compound. Astereoisomerically pure compound as used herein comprises greater thanabout 80% by weight of one stereoisomer of the compound, more preferablygreater than about 90% by weight of one stereoisomer of the compound,even more preferably greater than about 95% by weight of onestereoisomer of the compound, and most preferably greater than about 97%by weight of one stereoisomer of the compound. As used herein and unlessotherwise indicated, the term “stereoisomerically enriched” means acomposition that comprises greater than about 60% by weight of onestereoisomer of a compound, preferably greater than about 70% by weight,more preferably greater than about 80% by weight of one stereoisomer ofa compound. As used herein and unless otherwise indicated, the term“enantiomerically pure” means a stereoisomerically pure composition of acompound having one chiral center. Similarly, the term“stereoisomerically enriched” means a stereoisomerically enrichedcomposition of a compound having one chiral center. As used herein,stereoisomeric or diastereomeric mixtures means a composition thatcomprises more than one stereoisomer of a compound. A typicalstereoisomeric mixture of a compound comprises about 50% by weight ofone stereoisomer of the compound and about 50% by weight of otherstereoisomers of the compound, or comprises greater than about 50% byweight of one stereoisomer of the compound and less than about 50% byweight of other stereoisomers of the compound, or comprises greater thanabout 45% by weight of one stereoisomer of the compound and less thanabout 55% by weight of the other stereoisomers of the compound, orcomprises greater than about 40% by weight of one stereoisomer of thecompound and less than about 60% by weight of the other stereoisomers ofthe compound, or comprises greater than about 35% by weight of onestereoisomer of the compound and less than about 65% by weight of theother stereoisomers of the compound.

As used herein, the term “solid form” refers a crystal form or anamorphous form or a mixture thereof of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.In one embodiment, solid form refers to polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

It should also be noted the compounds herein can contain unnaturalproportions of atomic isotopes at one or more of the atoms. For example,the compounds may be radiolabeled with radioactive isotopes, such as forexample deuterium (²H), tritium (³H), iodine-125 (¹²⁵I), sulfur-35(³⁵S), or carbon-14 (¹⁴C), or may be isotopically enriched, such as withdeuterium (²H), carbon-13 (¹³C), or nitrogen-15 (¹⁵N). As used herein,an “isotopologue” is an isotopically enriched compound. The term“isotopically enriched” refers to an atom having an isotopic compositionother than the natural isotopic composition of that atom. “Isotopicallyenriched” may also refer to a compound containing at least one atomhaving an isotopic composition other than the natural isotopiccomposition of that atom. The term “isotopic composition” refers to theamount of each isotope present for a given atom. Radiolabeled andisotopically enriched compounds are useful as therapeutic agents, e.g.,cancer therapeutic agents, research reagents, e.g., binding assayreagents, and diagnostic agents, e.g., in vivo imaging agents. Allisotopic variations of the Compound 1 as described herein, whetherradioactive or not, are intended to be encompassed within the scope ofthe embodiments provided herein. In some embodiments, there are providedisotopologues of Compound 1, for example, the isotopologues aredeuterium, carbon-13, and/or nitrogen-15 enriched Compound 1. As usedherein, “deuterated”, means a compound wherein at least one hydrogen (H)has been replaced by deuterium (indicated by D or ²H), that is, thecompound is enriched in deuterium in at least one position.

It is understood that, independently of stereoisomerical or isotopiccomposition, each compound referred to herein can be provided in theform of any of the pharmaceutically acceptable salts discussed herein.Equally, it is understood that the isotopic composition may varyindependently from the stereoisomerical composition of each compoundreferred to herein. Further, the isotopic composition, while beingrestricted to those elements present in the respective compound or saltthereof, may otherwise vary independently from the selection of thepharmaceutically acceptable salt of the respective compound.

As used herein and unless otherwise indicated, the term “process(es)provided herein” refers to the methods disclosed herein which are usefulfor preparing Compound 1 provided herein. Modifications to the methodsdisclosed herein (e.g., starting materials, reagents, protecting groups,solvents, temperatures, reaction times, purification) are alsoencompassed by the present embodiments.

As used herein and unless otherwise indicated, the term “adding” or thelike means contacting one reactant, reagent, solvent, catalyst, or thelike with another reactant, reagent, solvent, catalyst, or the like.Reactants, reagents, solvents, catalysts, or the like can be addedindividually, simultaneously, or separately and can be added in anyorder. They can be added in the presence or absence of heat and canoptionally be added under an inert atmosphere.

As used herein and unless otherwise indicated, a reaction that is“substantially complete” or is driven to “substantial completion” meansthat the reaction contains more than about 80% by percent yield, in oneembodiment, more than about 90% by percent yield, in another embodiment,more than about 95% by percent yield, and in yet another embodiment,more than about 97% by percent yield of the desired product.

As used herein, and unless otherwise specified, the term “leaving group”refers to a stable moiety that can be detached from a molecule in abond-breaking step. In one embodiment, the leaving group includes, butis not limited to, a halogen, such as fluoro, chloro, bromo, iodo andmethanesulfonate (alternatively termed mesylate).

A “pharmaceutically acceptable excipient,” refers to a substance thataids the administration of an active agent to a subject by, for example,modifying the stability of an active agent or modifying the absorptionby a subject upon administration. A pharmaceutically acceptableexcipient typically has no significant adverse toxicological effect onthe patient. Examples of pharmaceutically acceptable excipients include,for example, water, NaCl (including salt solutions), normal salinesolutions, ½ normal saline, sucrose, glucose, bulking agents, buffers,binders, fillers, disintegrants, lubricants, coatings, sweeteners,flavors, alcohols, oils, gelatins, carbohydrates such as amylose orstarch, fatty acid esters, hydroxymethycellulose, polyvinyl pyrrolidine,and colors, and the like. One of skill in the art will recognize thatother pharmaceutical excipients known in the art are useful in thepresent invention and include those listed in for example the Handbookof Pharmaceutical Excipients, Rowe R. C., Shesky P. J., and Quinn M. E.,6^(th) Ed., The Pharmaceutical Press, RPS Publishing (2009). The terms“bulking agent”, and “buffer” are used in accordance with the plain andordinary meaning within the art.

As used herein, and unless otherwise specified, the term “about,” whenused in connection with doses, amounts, or weight percent of ingredientsof a composition or a dosage form, means dose, amount, or weight percentthat is recognized by those of ordinary skill in the art to provide apharmacological effect equivalent to that obtained from the specifieddose, amount, or weight percent is encompassed. Specifically, the term“about” contemplates a dose, amount, or weight percent within 30%, 25%,20%, 15%, 10%, or 5% of the specified dose, amount, or weight percent isencompassed.

As used herein, “administer” or “administration” refers to the act ofphysically delivering a substance as it exists outside the body into asubject. Administration includes all forms known in the art fordelivering therapeutic agents, including but not limited to topical,mucosal, injections, intradermal, intravenous, intramuscular delivery orother method of physical delivery described herein or known in the art(e.g., implantation of a slow-release device, such as a mini-osmoticpump to a subject; liposomal formulations; buccal; sublingual; palatal;gingival; nasal; vaginal; rectal; intra-arteriole; intraperitoneal;intraventricular; intracranial; or transdermal).

“Anti-cancer agents” refer to anti-metabolites (e.g., 5-fluoro-uracil,methotrexate, fludarabine), antimicrotubule agents (e.g., vincaalkaloids such as vincristine, vinblastine; taxanes such as paclitaxel,docetaxel), alkylating agents (e.g., cyclophosphamide, melphalan,carmustine, nitrosoureas such as bischloroethylnitrosurea andhydroxyurea), platinum agents (e.g. cisplatin, carboplatin, oxaliplatin,JM-216 or satraplatin, CI-973), anthracyclines (e.g., doxorubicin,daunorubicin), antitumor antibiotics (e.g., mitomycin, idarubicin,adriamycin, daunomycin), topoisomerase inhibitors (e.g., etoposide,camptothecins), anti-angiogenesis agents (e.g. Sutent®, sunitinibmalate, and Bevacizumab) or any other cytotoxic agents (estramustinephosphate, prednimustine), hormones or hormone agonists, antagonists,partial agonists or partial antagonists, kinase inhibitors, checkpointinhibitors, and radiation treatment.

An “effective amount” is an amount sufficient to achieve the effect forwhich it is administered (e.g., treat a disease or reduce one or moresymptoms of a disease or condition). Thus, administration of an “amount”of a compound described herein to a subject refers to administration of“an amount effective,” to achieve the desired therapeutic result. A“therapeutically effective amount” of a compound described herein forpurposes herein is thus determined by such considerations as are knownin the art. The term “therapeutically effective amount” of a compositiondescribed herein refers to the amount of the composition that, whenadministered, is sufficient to treat one or more of the symptoms of adisease described herein (e.g., cancer, for example AML, MDS, MPN orsolid tumors). Administration of a compound described herein can bedetermined according to factors such as, for example, the disease state,age, sex, and weight of the individual. A therapeutically effectiveamount also refers to any toxic or detrimental effects of Compound 1 areoutweighed by the therapeutically beneficial effects.

As used herein, and unless otherwise specified, the terms “treat,”“treating” and “treatment” refer to the eradication or amelioration of adisease or disorder, or of one or more symptoms associated with thedisease or disorder. In certain embodiments, the terms refer tominimizing the spread or worsening of the disease or disorder resultingfrom the administration of one or more prophylactic or therapeuticagents to a patient with such a disease or disorder. In someembodiments, the terms refer to the administration of a compoundprovided herein, with or without other additional active agent, afterthe onset of symptoms of the particular disease.

As used herein, and unless otherwise specified, the terms “prevent,”“preventing” and “prevention” refer to the prevention of the onset,recurrence or spread of a disease or disorder, or of one or moresymptoms thereof. In certain embodiments, the terms refer to thetreatment with or administration of a compound provided herein, with orwithout other additional active compound, prior to the onset ofsymptoms, particularly to patients at risk of diseases or disordersprovided herein. The terms encompass the inhibition or reduction of asymptom of the particular disease. Patients with familial history of adisease in particular are candidates for preventive regimens in certainembodiments. In addition, patients who have a history of recurringsymptoms are also potential candidates for the prevention. In thisregard, the term “prevention” may be interchangeably used with the term“prophylactic treatment.”

As used herein, and unless otherwise specified, the terms “manage,”“managing” and “management” refer to preventing or slowing theprogression, spread or worsening of a disease or disorder, or of one ormore symptoms thereof. Often, the beneficial effects that a patientderives from a prophylactic and/or therapeutic agent do not result in acure of the disease or disorder. In this regard, the term “managing”encompasses treating a patient who had suffered from the particulardisease in an attempt to prevent or minimize the recurrence of thedisease, or lengthening the time during which the remains in remission.

As used herein, the term “tumor,” refers to all neoplastic cell growthand proliferation, whether malignant or benign, and all pre-cancerousand cancerous cells and tissues. “Neoplastic,” as used herein, refers toany form of dysregulated or unregulated cell growth, whether malignantor benign, resulting in abnormal tissue growth. Thus, “neoplastic cells”include malignant and benign cells having dysregulated or unregulatedcell growth.

As used herein, “hematologic malignancy” refers to cancer of the body'sblood-forming and immune system-the bone marrow and lymphatic tissue.Such cancers include leukemias, lymphomas (Non-Hodgkin's Lymphoma),Hodgkin's disease (also called Hodgkin's Lymphoma) and myeloma. In oneembodiment, the myeloma is multiple myeloma. In some embodiments, theleukemia is, for example, acute myelogenous leukemia (AML), acutelymphocytic leukemia (ALL), adult T-cell leukemia, chronic lymphocyticleukemia (CLL), hairy cell leukemia, myelodysplasia, myeloproliferativedisorders or myeloproliferative neoplasm (MPN), chronic myelogenousleukemia (CML), myelodysplastic syndrome (MDS), human lymphotropicvirus-type 1 (HTLV 1) leukemia, mastocytosis, or B-cell acutelymphoblastic leukemia. In some embodiments, the lymphoma is, forexample, diffuse large B-cell lymphoma (DLBCL), B-cell immunoblasticlymphoma, small non-cleaved cell lymphoma, human lymphotropic virus-type1 (HTLV-1) leukemia/lymphoma, adult T-cell lymphoma, peripheral T-celllymphoma (PTCL), cutaneous T-cell lymphoma (CTCL), mantle cell lymphoma(MCL), Hodgkin lymphoma (HL), non-Hodgkin lymphoma (NHL), AIDS-relatedlymphoma, follicular lymphoma, small lymphocytic lymphoma,T-cell/histiocyte rich large B-cell lymphoma, transformed lymphoma,primary mediastinal (thymic) large B-cell lymphoma, splenic marginalzone lymphoma, Richter's transformation, nodal marginal zone lymphoma,or ALK-positive large B-cell lymphoma. In one embodiment, thehematological cancer is indolent lymphoma including, for example, DLBCL,follicular lymphoma, or marginal zone lymphoma. In one embodiment, thehematological malignancy is AML. In another embodiment, thehematological malignancy is MDS.

As used herein, the abbreviations for any protective groups, amino acidsand other compounds, are, unless indicated otherwise, in accord withtheir common usage, recognized abbreviations, or the IUPAC-IUBCommission on Biochemical Nomenclature (see, Biochem. 1972, 11:942-944).

If there is a discrepancy between a depicted structure and a name giventhat structure, the depicted structure is to be accorded more weight.Furthermore, if the stereochemistry of a structure or a portion thereofis not indicated, e.g., with bold or dashed lines, the structure orportion thereof is to be interpreted as encompassing all stereoisomersof it.

Polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide

Polymorph Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamideprovided herein is characterized by one or more X-ray powder diffractionpeaks at a two-theta angle of approximately 7.4, 11.5, 15.8, 16.7, 16.9,17.7, 18.4, 19.2, 19.5, 21.1, 23.4, 24.7, and 29.9, degrees 20 asdepicted in FIG. 1. In one embodiment, polymorph Form C of has one, two,three or four characteristic X-ray powder diffraction peaks at atwo-theta angle of approximately 16.7, 16.9, 17.7 and 24.7 degrees 2θ.In another embodiment, polymorph Form C has one, two, three, four, five,six or seven characteristic X-ray powder diffraction peaks as set forthin Table 1. In another embodiment, polymorph C of has one, two, or threecharacteristic X-ray powder diffraction peaks as set forth in Table 1.

TABLE 1 X-Ray Diffraction Peaks for Form C of Compound 1 Pos. d-spacingRel. Int. No. [°2Th.] [Å] [%] 1 7.36 12.0091 32.0 2 9.14 9.6750 8.3 311.51 7.6855 44.7 4 12.22 7.2420 4.9 5 15.17 5.8398 8.4 6 15.82 5.601131.8 7 16.68 5.3140 57.1 8 16.92 5.2392 86.8 9 17.72 5.0057 100.0 1018.39 4.8242 21.9 11 19.18 4.6268 36.4 12 19.45 4.5649 27.1 13 21.114.2077 40.4 14 21.82 4.0724 12.4 15 22.28 3.9902 12.0 16 22.57 3.939817.6 17 23.36 3.8082 24.7 18 24.26 3.6695 7.1 19 24.71 3.6026 72.5 2025.74 3.4615 16.9 21 26.03 3.4231 9.7 22 26.51 3.3627 17.7 23 27.883.1998 18.0 24 28.70 3.1104 6.9 25 29.91 2.9871 30.5 26 30.43 2.937510.7 27 30.83 2.9006 5.8 28 32.01 2.7960 16.6 29 37.94 2.3718 5.5

In one embodiment, polymorph Form C has the SEM picture as shown in FIG.2. In one embodiment, polymorph Form C has a thermogravimetric (TGA)thermograph corresponding substantially to the representative TGAthermogram as depicted in FIG. 3. In certain embodiments, polymorph FormC shows no TGA weight loss.

In one embodiment, polymorph Form C has a DSC thermogram correspondingsubstantially as depicted in FIG. 4. In certain embodiments, polymorphForm C is characterized by a DSC plot comprising melting event with anonset temperature of 232° C. and heat of fusion of 126 J/g.

In certain embodiments, polymorph Form C is characterized by dynamicvapor sorption analysis. A representative dynamic vapor sorption (DVS)isotherm plot is shown in FIG. 5. In certain embodiments, when therelative humidity (“RH”) is increased from about 0% to about 90% RH,polymorph Form C exhibits about 0.6% w/w water uptake. In certainembodiments, polymorph Form C comprises less than 0.1% water asdetermined in a coulometric Karl Fischer (KF) titrator equipped with anoven sample processor set at 225° C.

In certain embodiments, polymorph Form C shows no significantdegradation or residual solvent by ¹H NMR (FIG. 6).

In certain embodiments, polymorph Form C of Compound 1 is characterizedby its stability profile upon compression. In certain embodiments, FormC is stable, e.g., its XRPD pattern remains substantially unchanged withbroader diffraction peaks, upon application of 2000-psi pressure forabout 1 minute (FIG. 7).

In still another embodiment, the processes provided herein providepolymorph Form C that is substantially pure. In certain embodiments, thesubstantially pure polymorph Form C is substantially free of other solidforms, e.g., amorphous form. In certain embodiments, the purity of thesubstantially pure polymorph Form C is greater than 95%, greater than96%, greater than 97%, greater than 98%, greater than 98.5%, greaterthan 99%, greater than 99.5%, greater than 99.8% or greater than 99.9%.

Processes

In one embodiment, provided herein is a process for preparing Compound 1

comprising contacting an acid salt of3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione with2-(4-chlorophenyl)-2,2-difluoroacetic acid (Compound M) with2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of thionylchloride (SOCl₂), in a solvent under conditions suitable to provideCompound 1. In one embodiment, Compound M is the methanesulfonate,hydrochloride, sulfate, phosphate or acetate salt of3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione with2-(4-chlorophenyl)-2,2-difluoroacetic acid. In one embodiment, thesolvent is N-methyl pyrrolidone (NMP). In one embodiment, Compound M isthe methanesulfonate of of3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione with2-(4-chlorophenyl)-2,2-difluoroacetic acid.

In one embodiment, provided herein is a process for preparing Compound 1comprising contacting Compound L1 with2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of a base andpropylphosphonic anhydride (T3P), in a solvent, under conditionssuitable to provide Compound 1. In one embodiment, the base isN-methylmorpholine (NMM). In one embodiment, the solvent isdimethylformamide (DMF).

In one embodiment, provided herein is a process for preparing Compound 1

comprising contacting Compound L

with 2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence ofSOCl₂, in a solvent under conditions suitable to provide Compound 1. Inone embodiment, the solvent is NMP.

In one embodiment, provided herein is a process for preparing Compound 1

comprising contacting Compound L

with 2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of abase and T3P, in a solvent, under conditions suitable to provideCompound 1. In one embodiment, the base is NMM. In one embodiment, thesolvent is DMF. In one embodiment, the contacting is performed at atemperature between about 35° C. to about 40° C. In one embodiment, thecontacting is conducted for at least 12 hours.

In one embodiment, provided herein is a process for preparing Compound Mcomprising contacting Compound G

with a reducing agent, in a solvent, followed by contacting with anacid, under conditions suitable to provide Compound M. In oneembodiment, the acid is methanesulfonic acid, hydrochloric acid,sulfuric acid, phosphoric acid, or acetic acid. In one embodiment, thereducing agent is 5% or 10% palladium on carbon. In one embodiment, thesolvent comprises one or more solvents selected from NMP, 1-propanol,isopropyl alcohol, ethanol, tetrahydrofuran (THF) and optionally water.In one embodiment, the solvent comprises one or more of NMP, 1-propanol,isopropyl alcohol, ethanol and THF. In one embodiment, the solventcomprises isopropyl alcohol. In one embodiment, the solvent comprisesisopropyl alcohol and water. In one embodiment, the solvent comprisesisopropyl alcohol and water in a ratio of 1:4, 1:3 1:2 or 1:1 by volume.In one embodiment, the solvent comprises 1-propanol. In one embodiment,the solvent comprises 1-propanol and water in a ratio of 1:4, 1:3 1:2 or1:1 by volume. In one embodiment, the solvent comprises NMP, 1-propanoland isopropyl alcohol. In one embodiment, the solvent comprises NMP,ethanol and THF.

In one embodiment, provided herein is a process for preparing Compound L

comprising contacting Compound G

with a reducing agent, in a solvent, followed by contacting withmethanesulfonic acid, under conditions suitable to provide Compound L.In one embodiment, the reducing agent is 5% or 10% palladium on carbon.In one embodiment, the solvent comprises 1-propanol. In one embodiment,the solvent comprises isopropyl alcohol. In one embodiment, the solventcomprises 1-propanol and water. In one embodiment, the solvent comprisesisopropyl alcohol and water. In one embodiment, the solvent comprisesisopropyl alcohol and water in a ratio of 1:4, 1:3 1:2 or 1:1 by volume.In one embodiment, the solvent comprises 1-propanol and water in a ratioof 1:4, 1:3 1:2 or 1:1 by volume. In one embodiment, the solvent iswater, 1 propanol and isopropyl alcohol. In one embodiment, the solventcomprises NMP, 1-propanol, isopropyl alcohol, ethanol and THF. In oneembodiment, the contacting with the reducing agent is conducted under 35to 45 psi of H₂ pressure. In one embodiment, the contacting is performedat a temperature of about 25° to about 35° C. for at least 7 h.

In one embodiment, provided herein is a process for preparing3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione with2-(4-chlorophenyl)-2,2-difluoroacetic acid sulfate comprising contactingCompound G with a reducing agent, in a solvent, followed by contactingwith sulfuric acid acid, under conditions suitable to provide3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione with2-(4-chlorophenyl)-2,2-difluoroacetic acid sulfurate. In one embodiment,the reducing agent is 10% palladium on carbon. In one embodiment, thesolvent comprises NMP, 1-propanol and isopropyl alcohol.

In one embodiment, provided herein is a process for preparing3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione with2-(4-chlorophenyl)-2,2-difluoroacetic acid hydrochloride comprisingcontacting Compound G with a reducing agent, in a solvent, followed bycontacting with hydrochloric acid acid, under conditions suitable toprovide 3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dionewith 2-(4-chlorophenyl)-2,2-difluoroacetic acid hydrochloride. In oneembodiment, the reducing agent is 5% or 10% palladium on carbon. In oneembodiment, the solvent comprises NMP, ethanol and THF.

In one embodiment, provided herein is a process for preparing3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione with2-(4-chlorophenyl)-2,2-difluoroacetic acid phosphate comprisingcontacting Compound G with a reducing agent, in a solvent, followed bycontacting with phosphoric acid, under conditions suitable to provide3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione with2-(4-chlorophenyl)-2,2-difluoroacetic acid phosphorate. In oneembodiment, the reducing agent is 10% palladium on carbon. In oneembodiment, the solvent comprises NMP and ethanol.

In one embodiment, provided herein is a process for preparing Compound G

comprising contacting Compound X

wherein L¹ is a leaving group, with 3-aminopiperidine-2,6-dionehydrochloride in the presence of a salt, followed by a solvent and abase, under conditions suitable to provide Compound G. In oneembodiment, L¹ is halogen or methanesulfonate. In one embodiment, L¹ ischloro or methanesulfonate. In one embodiment, the salt is potassiumbromide or potassium iodide. In one embodiment, the base isN,N-diisopropylethylamine (DIPEA). In one embodiment, the solventcomprises acetonitrile and water. In one embodiment, the contacting isconducted at about 75° C. to about 80° C. for about 16 hours.

In one embodiment, provided herein is a process for preparing Compound G

comprising contacting Compound D

with 3-aminopiperidine-2,6-dione hydrochloride in the presence of asalt, followed by a solvent and a base, under conditions suitable toprovide Compound G. In one embodiment, the salt is potassium bromide orpotassium iodide. In one embodiment, the base is DIPEA. In oneembodiment, the solvent comprises acetonitrile and water. In oneembodiment, the solvent comprises acetonitrile. In one embodiment, thecontacting is conducted at about 75° C. to about 80° C. for about 16hours.

In one embodiment, provided herein is a process for preparing Compound G

comprising contacting Compound D1

with 3-aminopiperidine-2,6-dione hydrochloride in the presence of asalt, followed by a solvent and a base, under conditions suitable toprovide Compound G. In one embodiment, the salt is potassium bromide orpotassium iodide. In one embodiment, the base is DIPEA. In oneembodiment, the solvent comprises acetonitrile and water. In oneembodiment, the solvent comprises acetonitrile. In one embodiment, thecontacting is conducted at about 75° C. to about 80° C. for about 16hours.

In one embodiment, provided herein is a process for preparing Compound G

comprising contacting Compound D

with 3-aminopiperidine-2,6-dione hydrochloride in the presence of abase, followed by a solvent and a salt to obtain a reaction mixture,under conditions suitable to provide Compound G. In one embodiment, thesalt is potassium bromide or potassium iodide. In one embodiment, thebase is DIPEA. In one embodiment, the solvent comprises acetonitrile andwater. In one embodiment, the solvent comprises acetonitrile. In oneembodiment, the contacting is conducted at about 75° C. to about 80° C.for about 16 hours. In certain embodiments, the reaction mixture iscontacted with acetic acid.

In one embodiment, provided herein is a process for preparing Compound G

comprising contacting Compound D1

with 3-aminopiperidine-2,6-dione hydrochloride in the presence of abase, followed by a solvent and a salt to obtain a reaction mixture,under conditions suitable to provide Compound G. In one embodiment, thesalt is potassium bromide or potassium iodide. In one embodiment, thebase is DIPEA. In one embodiment, the solvent comprises acetonitrile andwater. In one embodiment, the solvent comprises acetonitrile. In oneembodiment, the contacting is conducted at about 75° C. to about 80° C.for about 16 hours. In certain embodiments, the reaction mixture iscontacted with acetic acid.

In one embodiment, provided herein is a process for preparing Compound D

comprising contacting Compound A

with 1) dimethyl sulfate in a solvent; 2) a base; 3) methanesulfonylchloride (MsCl), and 4) lithium chloride (LiCl), under conditionssuitable to provide Compound D. In one embodiment, the solvent isdimethylacetamide (DMAc). In one embodiment, the base is NMM. In oneembodiment, the process comprises contacting Compound A with dimethylsulfate in a solvent at about 10° C. for about 3 hours to obtain aslurry. In one embodiment, the slurry is contacted with a base, followedby methanesulfonyl chloride at about 10° C. to about 15° C. for betweenabout 30 minutes and about 60 minutes. In one embodiment, the slurry isfurther contacted with lithium chloride.

In one embodiment, provided herein is a process for preparing CompoundD1

comprising contacting Compound A

with 1) dimethyl sulfate in a solvent; 2) a base; and 3) methanesulfonicanhydride (Ms₂O), under conditions suitable to provide Compound D1. Inone embodiment, the solvent is DMAc. In one embodiment, the base is NMM.In one embodiment, the process comprises contacting Compound A in asolvent at about 20-25° C. with dimethyl sulfate to obtain a slurry. Inone embodiment, the slurry is contacted with a base, followed by Ms₂O inDMAc at about 20-25° C.

In one embodiment, provided herein is a process for preparing Compound A

comprising contacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with a base, in a solvent, under conditions suitable to provide CompoundA. In one embodiment, the base is potassium hydroxide. In oneembodiment, the solvent comprises isopropyl alcohol and water. In oneembodiment, the contacting is conducted at about 35° C. to about 40° C.for about 2 hours.

In one embodiment, provided herein is a process for preparing Compound 1

comprising contacting Compound L

with 2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of NMPand SOCl₂, under conditions suitable to provide Compound 1.

In one embodiment, provided herein is a process for preparing Compound 1

comprising contacting Compound L

with 2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of DMF,NMM and T3P, under conditions suitable to provide Compound 1.

In one embodiment, provided herein is a process for preparing Compound 1

comprising

-   -   a) contacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with a first base in a first solvent, under conditions suitable toprovide Compound A

-   -   b) contacting Compound A with 1) dimethyl sulfate in a second        solvent, 2) a second base, 3) methanesulfonyl chloride, and 4)        lithium chloride, under conditions suitable to provide Compound        D

-   -   c) contacting Compound D with i) 3-aminopiperidine-2,6-dione        hydrochloride in the presence of a salt, followed by ii) a third        solvent and iii) a third base, under conditions suitable to        provide Compound G,

-   -   d) contacting Compound G with a reducing agent in a fourth        solvent followed by methanesulfonic acid, under conditions        suitable to provide Compound L

-   -   and    -   e) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of        SOCl₂ in a fifth solvent, under conditions suitable to provide        2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

In one embodiment, the first base is potassium hydroxide. In oneembodiment, the first solvent is isopropyl alcohol. In one embodiment,the second base is NMM. In one embodiment, the second solvent is DMAc.In one embodiment, the third base is DIPEA. In one embodiment, the thirdsolvent is acetonitrile and water. In one embodiment, the third solventis acetonitrile. In one embodiment, the fourth solvent is propanol andwater. In one embodiment, the fifth solvent is NMP.

In one embodiment, provided herein is a process for preparing Compound 1

comprising

-   -   a) contacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with a first base in a first solvent, under conditions suitable toprovide Compound A

-   -   b) contacting Compound A with 1) dimethyl sulfate in a second        solvent, 2) a second base, 3) methanesulfonyl chloride, and 4)        lithium chloride, under conditions suitable to provide Compound        D

-   -   c) contacting Compound D with i) 3-aminopiperidine-2,6-dione        hydrochloride in the presence of a salt, followed by ii) a third        solvent and iii) a third base, under conditions suitable to        provide Compound G,

-   -   d) contacting Compound G with a reducing agent in a fourth        solvent followed by methanesulfonic acid, under conditions        suitable to provide Compound L

-   -   and    -   e) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of        T3P in a fifth solvent and a fourth base, under conditions        suitable to provide        2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

In one embodiment, the first base is potassium hydroxide. In oneembodiment, the first solvent is isopropyl alcohol. In one embodiment,the second base is NMM. In one embodiment, the second solvent is DMAc.In one embodiment, the third base is DIPEA. In one embodiment, the thirdsolvent is acetonitrile and water. In one embodiment, the third solventis acetonitrile. In one embodiment, the fourth solvent is propanol,water and isopropyl alcohol. In one embodiment, the fifth solvent isDMF. In one embodiment, the fourth base is NMM.

In one embodiment, provided herein is a process for preparing Compound 1

comprising

-   -   a) contacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with a potassium hydroxide in isopropyl alcohol, under conditionssuitable to provide Compound A

-   -   b) contacting Compound A with 1) dimethyl sulfate in DMAc, 2)        NMM, 3) methanesulfonyl chloride, and 4) lithium chloride, under        conditions suitable to provide Compound D

-   -   c) contacting Compound D with i) 3-aminopiperidine-2,6-dione        hydrochloride in the presence of a potassium bromide or        potassium iodide, followed by ii) acetonitrile and water or        acetonitrile only and iii) DIPEA, under conditions suitable to        provide Compound G,

-   -   d) contacting Compound G with a reducing agent in water and        propanol followed by methanesulfonic acid, under conditions        suitable to provide Compound L

-   -   and    -   e) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of        SOCl₂ in NMP, under conditions suitable to provide        2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

In one embodiment, provided herein is a process for preparing Compound 1

comprising

-   -   a) contacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with potassium hydroxide in isopropyl alcohol, under conditions suitableto provide Compound A

-   -   b) contacting Compound A with 1) dimethyl sulfate in DMAc, 2)        NMM, 3) methanesulfonyl chloride, and 4) lithium chloride, under        conditions suitable to provide Compound D

-   -   c) contacting Compound D with i) 3-aminopiperidine-2,6-dione        hydrochloride in the presence of potassium bromide or potassium        iodide, followed by ii) a solvent comprising acetonitrile and        water, iii) DIPEA, and iv) acetic acid, under conditions        suitable to provide Compound G,

-   -   d) contacting Compound G with 10% wt Pd/C, methanesulfonic acid,        and a solvent comprising water and 1-propanol, under conditions        suitable to provide Compound L

-   -   and    -   e) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of        DMF, NMM and T3P, under conditions suitable to provide Compound        1.

In one embodiment, provided herein is a process for preparing Compound 1

comprising

-   -   a) contacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with potassium hydroxide in isopropyl alcohol, under conditions suitableto provide Compound A

-   -   b) contacting Compound A with 1) dimethyl sulfate in DMAc, 2)        NMM, 3) methanesulfonyl chloride, and 4) lithium chloride, under        conditions suitable to provide Compound D

-   -   c) contacting Compound D with i) 3-aminopiperidine-2,6-dione        hydrochloride in the presence of potassium bromide or potassium        iodide, followed by ii) a solvent comprising acetonitrile and        water, iii) DIPEA, and iv) acetic acid, under conditions        suitable to provide Compound G,

-   -   d) contacting Compound G with 10% wt Pd/C, methanesulfonic acid,        and a solvent comprising water, 1-propanol and isopropyl        alcohol, under conditions suitable to provide Compound L

-   -   and    -   e) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of        DMF, NMM and T3P, under conditions suitable to provide Compound        1.

In one embodiment, provided herein is a process for preparing polymorphForm C of Compound 1 comprising contacting Compound 1 obtained in theprocesses provided herein with formic acid and water at about 55° C. toabout 65° C. for at least 16 hours to obtain polymorph Form C ofCompound 1. In one embodiment, the process further comprises cooling thereaction mixture to between about 15° C. and about 25° C.

In one embodiment, provided herein is a process for preparing polymorphForm C of Compound 1 comprising contacting Compound 1 obtained in theprocesses provided herein with acetone to obtain a mixture, heating themixture under nitrogen to between about 70° C. and about 75° C. withagitation, cooling the mixture to room temperature, and filtering themixture to obtain a cake. The cake is washed with acetone and dried toobtain Form C of Compound 1.

In one embodiment, provided herein is a process for preparing polymorphForm C of Compound 1 comprising

-   -   a) contacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with potassium hydroxide in isopropyl alcohol, under conditions suitableto provide Compound A

-   -   b) contacting Compound A with 1) dimethyl sulfate in DMAc, 2)        NMM, 3) methanesulfonyl chloride, and 4) lithium chloride, under        conditions suitable to provide Compound D

-   -   c) contacting Compound D with i) 3-aminopiperidine-2,6-dione        hydrochloride in the presence of potassium bromide or potassium        iodide, followed by ii) a solvent comprising acetonitrile, water        and acetic acid, and iii) DIPEA, under conditions suitable to        provide Compound G,

-   -   d) contacting Compound G with 10% wt Pd/C, methanesulfonic acid,        and a solvent comprising water and 1-propanol, under conditions        suitable to provide Compound L

-   -   e) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of        DMF, NMM and T3P, under conditions suitable to provide Compound        1, and    -   f) contacting Compound 1 with formic acid and water to obtain        polymorph Form C of Compound 1.

In one embodiment, provided herein is a process for preparing polymorphForm C of Compound 1 comprising

-   -   a) contacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with potassium hydroxide in isopropyl alcohol, under conditions suitableto provide Compound A

-   -   b) contacting Compound A with 1) dimethyl sulfate in DMAc, 2)        NMM, 3) methanesulfonyl chloride, and 4) lithium chloride, under        conditions suitable to provide Compound D

-   -   c) contacting Compound D with i) 3-aminopiperidine-2,6-dione        hydrochloride in the presence of potassium bromide or potassium        iodide, followed by ii) a solvent comprising acetonitrile and        water, iii) DIPEA, and iv) acetic acid under conditions suitable        to provide Compound G,

-   -   d) contacting Compound G with 10% wt Pd/C, methanesulfonic acid,        and a solvent comprising water and 1-propanol, under conditions        suitable to provide Compound L

-   -   e) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of        DMF, NMM and T3P, under conditions suitable to provide Compound        1, and    -   f) contacting Compound 1 with formic acid and water to obtain        polymorph Form C of Compound 1.

In one embodiment, provided herein is a process for preparing polymorphForm C of Compound 1 comprising

-   -   a) contacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with potassium hydroxide in isopropyl alcohol, under conditions suitableto provide Compound A

-   -   b) contacting Compound A with 1) dimethyl sulfate in DMAc, 2)        NMM, 3) methanesulfonyl chloride, and 4) lithium chloride, under        conditions suitable to provide Compound D

-   -   c) contacting Compound D with i) 3-aminopiperidine-2,6-dione        hydrochloride in the presence of potassium bromide or potassium        iodide, followed by ii) a solvent comprising acetonitrile and        water, iii) DIPEA, and iv) acetic acid, under conditions        suitable to provide Compound G,

-   -   d) contacting Compound G with 10% wt Pd/C, methanesulfonic acid,        and a solvent comprising water, 1-propanol and isopropyl        alcohol, under conditions suitable to provide Compound L

-   -   and    -   e) contacting Compound L with        2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of        DMF, NMM and T3P, under conditions suitable to provide Compound        1, and    -   f) contacting Compound 1 with formic acid and water at about        55° C. to about 65° C. for at least about 16 hours to obtain        polymorph Form C of Compound 1.

In one embodiment, the processes herein provide improved yield ofpolymorph Form C of Compound 1 as compared to the processes in the art.In one embodiment, the processes herein provide about 2 to about 9 foldimproved yield of polymorph Form C of Compound 1 as compared to theprocesses in the art. In one embodiment, the processes herein provideover 2, 3, 4, 5, 6, 7, 8 or 9 fold improved yield of polymorph Form C ofCompound 1 as compared to the processes in the art. In one embodiment,the processes herein provide about 9 fold improved yield of polymorphForm C of Compound 1 as compared to the processes in the art.

In one embodiment, the processes herein provide polymorph Form C ofCompound 1 in overall yield of about 40% or more. In one embodiment, theprocesses herein provide polymorph Form C of Compound 1 in overall yieldof about 45% or more. In one embodiment, the processes herein providepolymorph Form C of Compound 1 in overall yield of about 50% or more. Inone embodiment, the processes herein provide polymorph Form C ofCompound 1 in overall yield of about 45% to about 55%. In oneembodiment, the processes herein provide polymorph Form C of Compound 1in overall yield of about 53%.

In one embodiment, the processes herein provide an improvement in yieldof Compound 1 as compared to the processes known in the art. In oneembodiment, the yield of Compound 1 in the processes provided herein isabout 50% to about 55%, whereas the yield in the processes known in theart is about 6%. In one embodiment, the yield of Compound 1 in theprocesses provided herein is about 53%.

In one embodiment, the processes herein provide polymorph Form C ofCompound 1 having a purity of about 99% to about 100%. In oneembodiment, the processes herein provide polymorph Form C of Compound 1having a purity of about 99.9%. In one embodiment, the processes hereinprovide polymorph Form C of Compound 1 having no detectable impurities.

In one embodiment, the improvement in the processes provided herein ascompared to the processes known in the art includes use of inexpensivestarting material, for example 5-cyano phthalide. In one embodiment, theimprovement in the processes provided herein as compared to theprocesses known in the art includes improved safety. In one embodiment,the process provided herein eliminates the potentially unsafe radicalreaction employing N-bromosuccinimide. In one embodiment, theimprovement in the processes provided herein as compared to theprocesses known in the art includes improved efficiency. In oneembodiment, the processes provided herein result in improved yields. Inone embodiment, the processed provided here are simplified, for example,no silica gel chromatography is used throughout the entire process. Inone embodiment, the improvement in the processes provided herein ascompared to the processes known in the art includes less toxic andenvironmentally friendly reaction conditions. In one embodiment, theprocesses provided herein eliminate the highly toxic KCN reagent in thepreviously reported process, thereby avoiding waste containing toxiccyanide.

In certain embodiments, provided herein are chemical intermediatesuseful in the methods provided herein. In certain embodiments, providedherein are chemical intermediates useful in the synthesis of Compound 1.

In one embodiment, provided herein is Compound A

In one embodiment, provided herein is Compound X

where L¹ is a leaving group. In one embodiment, L¹ is halogen ormethanesulfonate. In one embodiment, L¹ is chloro or methanesulfonate.

In one embodiment, provided herein is Compound D

In one embodiment, provided herein is Compound D1

Synthetic Schemes

In certain embodiments, Compound 1 is prepared as outlined in schemes 1or 2 shown below, as well as in the examples set forth in the Examplesection. It should be noted that one skilled in the art can modify theprocedures set forth in the illustrative schemes and examples to arriveat the desired product.

Methods of Use

Compound 1 described herein has utility in methods of treating cancer.Described herein is Compound 1 for use in methods of treating cancer.Exemplary methods of treating cancer comprising administering Compound 1are described in US Publication No. US 2019/003018 A1.

In the following, embodiments are provided herein that include allpossible combinations of the particular embodiments set forth herein.

In one embodiment, provided herein are methods for inhibition of diseaseprogression, inhibition of tumor growth, reduction of primary tumor,relief of tumor-related symptoms, inhibition of tumor secreted factors,delaying appearance of primary or secondary tumors, slowing developmentof primary or secondary tumors, decreasing occurrence of primary orsecondary tumors, slowing or decreasing severity of secondary effects ofdisease, arresting tumor growth and regression of tumors, increasingtime to progression, increasing progression free survival, increasingoverall survival in a cancer patient, or one or more thereof, comprisingadministering an effective amount of Compound 1 to the patient. In oneembodiment, provided herein is Compound 1 for use in methods forinhibition of disease progression, inhibition of tumor growth, reductionof primary tumor, relief of tumor-related symptoms, inhibition of tumorsecreted factors, delaying appearance of primary or secondary tumors,slowing development of primary or secondary tumors, decreasingoccurrence of primary or secondary tumors, slowing or decreasingseverity of secondary effects of disease, arresting tumor growth andregression of tumors, increasing time to progression, increasingprogression free survival, increasing overall survival in a cancerpatient, or one or more thereof, comprising administering an effectiveamount of Compound 1 to the patient.

Also provided herein is Compound 1 for use in methods of treating anydisease provided herein related to by Compound 1.

In certain embodiments, the cancer is a solid tumor or a hematologicalcancer. In certain embodiments, the cancer is interleukin-3 (IL-3)independent. In certain embodiments, the cancer is a solid tumor. Incertain embodiments, the solid tumor is metastatic. In certainembodiments, the solid tumor is drug-resistant.

In certain embodiments, cancer refers to a disease of skin tissues,organs, blood, and vessels. In certain embodiments, the cancer is asolid tumor, including, but not limited to, cancers of the bladder,bone, blood, brain, breast, cervix, chest, colon, endometrium,esophagus, eye, head, kidney, liver, lymph nodes, lung, mouth, neck,ovaries, pancreas, prostate, rectum, stomach, testis, throat, anduterus. Specific cancers include, but are not limited to, advancedmalignancy, amyloidosis, neuroblastoma, meningioma, hemangiopericytoma,multiple brain metastase, glioblastoma multiforms, glioblastoma, brainstem glioma, poor prognosis malignant brain tumor, malignant glioma,recurrent malignant glioma, anaplastic astrocytoma, anaplasticoligodendroglioma, neuroendocrine tumor, rectal adenocarcinoma,colorectal cancer, including stage 3 and stage 4, unresectablecolorectal carcinoma, metastatic hepatocellular carcinoma, Kaposi'ssarcoma, karyotype acute myeloblastic leukemia, Hodgkin's lymphoma,non-Hodgkin's lymphoma, cutaneous T-Cell lymphoma, cutaneous B-Celllymphoma, diffuse large B-Cell lymphoma, low grade follicular lymphoma,malignant melanoma, malignant mesothelioma, malignant pleural effusionmesothelioma syndrome, peritoneal carcinoma, papillary serous carcinoma,gynecologic sarcoma, soft tissue sarcoma, scleroderma, cutaneousvasculitis, Langerhans cell histiocytosis, leiomyosarcoma,fibrodysplasia ossificans progressive, hormone refractory prostatecancer, resected high-risk soft tissue sarcoma, unresectablehepatocellular carcinoma, Waldenstrom's macroglobulinemia, smolderingmyeloma, indolent myeloma, fallopian tube cancer, androgen independentprostate cancer, androgen dependent stage IV non-metastatic prostatecancer, hormone-insensitive prostate cancer, chemotherapy-insensitiveprostate cancer, carcinoma, including papillary thyroid carcinoma,follicular thyroid carcinoma, and medullary thyroid carcinoma, andleiomyoma.

In certain embodiments, the cancer is leukemia, lymphoma, Hodgkin'sdisease or myeloma. In one embodiment, the myeloma is multiple myeloma.In some embodiments, the leukemia is, for example, acute myelogenousleukemia (AML), acute lymphocytic leukemia (ALL), adult T-cell leukemia,chronic lymphocytic leukemia (CLL), hairy cell leukemia, myelodysplasia,myeloproliferative disorders or myeloproliferative neoplasm (MPN),chronic myelogenous leukemia (CML), myelodysplastic syndrome (MDS),human lymphotropic virus-type 1 (HTLV 1) leukemia, mastocytosis, orB-cell acute lymphoblastic leukemia. In some embodiments, the lymphomais, for example, diffuse large B-cell lymphoma (DLBCL), B-cellimmunoblastic lymphoma, small non-cleaved cell lymphoma, humanlymphotropic virus-type 1 (HTLV-1) leukemia/lymphoma, adult T-celllymphoma, peripheral T-cell lymphoma (PTCL), cutaneous T-cell lymphoma(CTCL), mantle cell lymphoma (MCL), Hodgkin lymphoma (HL), non-Hodgkinlymphoma (NHL), AIDS-related lymphoma, follicular lymphoma, smalllymphocytic lymphoma, T-cell/histiocyte rich large B-cell lymphoma,transformed lymphoma, primary mediastinal (thymic) large B-celllymphoma, splenic marginal zone lymphoma, Richter's transformation,nodal marginal zone lymphoma, or ALK-positive large B-cell lymphoma. Inone embodiment, the hematological cancer is indolent lymphoma including,for example, DLBCL, follicular lymphoma, or marginal zone lymphoma. Inone embodiment, the hematological malignancy is AML. In anotherembodiment, the hematological malignancy is MDS.

In one embodiment, provided herein are methods of treating cancercomprising administering Compound 1 in combination with one or moresecond active agents, and optionally in combination with radiationtherapy, blood transfusions, or surgery. In one embodiment, providedherein is Compound 1 for use in methods of treating cancer comprisingadministering Compound 1 in combination with one or more second activeagents, and optionally in combination with radiation therapy, bloodtransfusions, or surgery. In one embodiment, the second active agent isan anti-cancer agent. In one embodiment, the second active agent isselected from a JAK inhibitor, FLT3 inhibitor, mTOR inhibitor,spliceosome inhibitor, BET inhibitor, SMG1 inhibitor, ERK inhibitors,LSD1 inhibitor, BH3 mimetic, topoisomerase inhibitor, and RTK inhibitor.

Pharmaceutical Compositions and Routes of Administration

Compound 1 prepared by the processes provided herein is useful for thepreparation of pharmaceutical compositions, comprising an effectiveamount of Compound 1 and a pharmaceutically acceptable excipient,carrier or vehicle. In some embodiments, the pharmaceutical compositiondescribed herein are suitable for oral, parenteral, mucosal, transdermalor topical administration.

EXAMPLES

The following abbreviations were used in descriptions and examples:

ACN or MeCN: Acetonitrile

AcOH: Acetic acid

AIBN: Azo-isobutyronitrile

DAST: Diethylaminosulfur trifluoride

DIEA or DIPEA or iPr₂NEt: N,N-diisopropylethylamine

DMA or DMAc: Dimethylacetamide

DMF: Dimethylformamide

DMS: Dimethyl sulfate

DPPF: 1,1′ Bis(diphenylphosphino)ferrocene

EDC: 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide

HOBt: Hydroxybenzotriazole

HPLC: High performance liquid chromatography

IPA or i-PrOH: Isopropyl alcohol

MeOH: Methanol

Me₂SO₄: Dimethyl sulfate

MsCl: Methanesulfonyl chloride

Ms₂O: Methanesulfonic anhydride

MsOH: Methanesulfonic acid

NBS: N-Bromosuccinimide

NMM: N-methyl morpholine

Pd₂(dba)₃: Tris(dibenzylideneacetone)dipalladium(0)

1-PrOH: 1-Propyl alcohol

T3P: Propylphosphonic anhydride

TEA: Triethylamine

RT: Room temperature

Zn(OAC)₂: Zinc acetate

The following Examples are presented by way of illustration, notlimitation.

Example 1 (Reference Example) Synthesis of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide

The title compound was prepared as described in U.S. Pat. No. 9,499,514B2, according to the following reaction scheme

Overall yield of the title compound in this process is about 6.4%.

Example 2 Synthesis of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide

The title compound was prepared according to the following reactionscheme

Overall yield of the title compound in this process is about 53%. TheHPLC purity of polymorph Form C is obtained in this process is >99.9%.No detectable impurities were found in the final product.

Example 3 Synthesis of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide

The title compound was prepared according to the following reactionscheme

Overall yield of the title compound in this process is about 53%. TheHPLC purity of polymorph Form C is obtained in this process is >99.9%.No detectable impurities were found in the final product.

The synthetic steps are described below:

Step 1: Synthesis of potassium 4-cyano-2-(hydroxymethyl)benzoate

A slurry of the lactone (100.0 g) in i-PrOH (990 mL) and water (10 mL)was stirred in a reactor at ambient temperature. Potassium hydroxide(43.6 g as 86.9 wt % pellets, 1.08 equiv.) was charged as a solid. Theresulting slurry was heated to T_(i)=35-40° C. and held at thattemperature for 2 h. The slurry was cooled to 20-25° C., and then wasfiltered. The cake was washed with a mixture of i-PrOH and water. Thecake was dried at 20-25° C. under vacuum and a N₂ sweep. Typical yieldwas 97%. ¹H NMR (300 MHz, DMSO-d6) 4.50 (d, J=6 Hz, 2H), 7.34 (t, J=6Hz, 1H), 7.62 (d, J=9 Hz, 1H), 7.66 (s, 1H), 7.78 (d, J=9 Hz, 1H).

Step 2: Synthesis of methyl 2-(chloromethyl)-4-cyanobenzoate

The K salt A (50.0 g) was slurried in DMAc (500 mL) at 10° C. in a threeneck flask with overhead stirring. Me₂SO₄ (33.7 g, 25.3 mL, 1.05 equiv.)was added over 30-60 minutes at 10° C. The resulting slurry was aged atthis temperature for 3 h. NMM (2.0 equiv.) was then added to the slurry,followed by the slow addition of MsCl over 30 minutes, maintaining10-15° C. The resulting slurry was aged at this temperature for 30minutes. LiCl (1.0 equiv.) was added as a solid in a single portion. Theresulting slurry was heated to 35-40° C. for 1-2 h. The slurry wascooled to 20-25° C. over 30-60 minutes. H₂O (200 mL) was added over 20minutes to the reaction slurry, maintaining 25-30° C. The resultingsolution was then seeded with the desired product. After 20-30 minutes,H₂O addition (500 mL) resumed over 2 h. After 1-2 h aging, the slurrywas filtered. The cake was washed with 3:2 H₂O:DMAc (200 mL) then withH₂O (100 mL). The obtained solid was dried at 20-25° C. under vacuum anda N₂ sweep. Typical yield was 85%. ¹H NMR (300 MHz, CDCl3-d) 3.97 (s,3H), 5.04 (s, 2H), 7.69 (dd, J=3, 9 Hz, 1H), 7.90 (d, J=3 Hz, 1H), 8.06(d, J=9 Hz, 1H).

Step 3: Synthesis of2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindoline-5-carbonitrile

To a 100 mL reactor was charged D (7.00 g), 3-aminopiperidine-2,6-dionehydrochloride (6.05 g), and potassium bromide (3.97 g). followed byacetonitrile (56 mL), water (3.5 mL), and diisopropylethylamine (13.1mL). The system, including reactor and pipes, was inserted by blowinggently with nitrogen, heated to 75-80° C. and aged (16 hours). Thereaction was then cooled to 20° C. over 1 h. Glacial acetic acid (0.48mL) was charged, then aged (1 h). Water (59.5 mL) was then charged tothe mixture over 2 hours, and then the mixture was aged (1 h). Uponcompletion of the aging process, the reaction was filtered and the wetcake was then washed with a mixture of (1:1) acetonitrile:water (14 g),then washed with water (14 g). The resulting wet cake was then dried ina vac oven at 20° C. with a nitrogen bleed to yield G (7.00 g) as alight blue/purple solid. Typical yields are 75-90%. ¹H NMR (300 MHz,DMSO-d₆) δ ppm 11.03 (s, 1H), 8.16 (s, 1H), 7.99 (dd, J=7.80, 0.90 Hz,1H), 7.91 (d, J=7.80 Hz, 1H), 5.15 (dd, J=13.26, 5.10 Hz, 1H), 4.49 (q,J=18 Hz, 2H), 2.92 (ddd, J=17.5, 13.5, 5.4 Hz, 1H), 2.60 (br d, J=17.7Hz, 1H), 2.48-2.349 (m, 1H), 2.07-1.99 (m, 1H); Anal. Calcd forC₁₄H₁₁N₃O₃: C, 62.45; H, 4.12; N, 15.61; O, 17.83. Found: C, 62.17; H,4.02; N, 15.57.

Step 4: Synthesis of3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dionemethanesulfonic acid

To a slurry of2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindoline-5-carbonitrile (G, 20 g,74.3 mmol), 5% Pd/C (1.5 g, 7.5% wt), water (100 mL) and n-propanol (44mL) was added methanesulfonic acid (10.8 g, 112 mmol). The mixture wasagitated under 35 to 45 psi of H₂ pressure at 25 to 35° C. for at least7 h and then filtered over Celite at 25 to 35° C. The solid was washedwith n-propanol and water (1:4 by vol, 20 mL). The combined filtrate wasextracted with anisole (120 mL) twice. To the resulting aqueous layerwas added IPA (280 mL) and seeded at 30° C. followed by additional IPA(180 mL). The batch was cooled to 0 to 10° C., filtered and washed witha mixture of IPA and water (30 mL, 4:1 by volume) then IPA (40 mL). Thesolid was dried under vacuum at 40° C. to give3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dionemethanesulfonic acid (L) as white solid (22.8 g, 83% yield). ¹H NMR (300MHz, DMSO-d₆) δ ppm 1.94-2.08 (m, 1H) 2.32 (s, 3H) 2.41 (br dd, J=13.07,4.36 Hz, 1H) 2.54-2.68 (m, 1H) 2.80-3.04 (m, 1H) 4.17 (s, 2H) 4.41 (dd,J=26.60, 18.20 Hz, 2H) 5.13 (dd, J=13.25, 5.00 Hz, 1H) 7.60 (d, J=7.89Hz, 1H) 7.69 (s, 1H) 7.79 (d, J=7.79 Hz, 1H) 8.24 (br s, 3H) 11.00 (brs, 1H). MS (ESI) m/z 274 [M+1]⁺.

Alternate Step 4:3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dioneMethanesulfonic acid

To a slurry of2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindoline-5-carbonitrile (50 g, 186mmol), 10% palladium on carbon, 50% water-wet (5.0 g) and 1-PrOH (500mL) was added methanesulfonic acid (26.8 g, 279 mmol) followed by tworinses of 1-PrOH (10 mL each). 1-PrOH (480 mL) was added to theresulting slurry. The mixture was agitated under 35 to 45 psi of H₂pressure at 35 to 45° C. for at least 5 hours and then cooled to 20 to30° C. followed by addition of water (700 mL) and agitation at 20 to 30°C. for at least 1 h. To this mixture was added Si-Thiol (11.8 g,Silicycle, 40-63 um, loading: 1.30 mmol/g) and the resulting mixture wasagitated at 20 to 30° C. for 18 hours. The mixture was filtered overCelite (10 g) and filtered solids were washed twice with 1-PrOH:water(1:1 by vol, 50 mL). The process were repeated 4 times before thefiltrates were combined in one batch as 200 g scale reaction fordownstream process.

The combined filtrates (200 g scale) were vacuum distilled to 200 to 240mL batch volume followed by continuous vacuum distillation whilecharging 1-PrOH until batch water content reached 20 to 30% wt. Theresulting reaction mixture was cooled to 20 to 25° C. over 1 h and heldat 20 to 25° C. for at least 2 hours. The mixture was filtered, washedwith 1-PrOH:water (200 mL, 4:1 by vol) and 1-PrOH (300 mL), and driedunder vacuum at 40 to 50° C. to give3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dionemethanesulfonic acid as white solid (237 g, 88% yield). ¹H NMR (300 MHz,DMSO-d₆) δ ppm 1.94-2.08 (m, 1H) 2.32 (s, 3H) 2.41 (br dd, J=13.07, 4.36Hz, 1H) 2.54-2.68 (m, 1H) 2.80-3.04 (m, 1H) 4.17 (s, 2H) 4.41 (dd,J=26.60, 18.20 Hz, 2H) 5.13 (dd, J=13.25, 5.00 Hz, 1H) 7.60 (d, J=7.89Hz, 1H) 7.69 (s, 1H) 7.79 (d, J=7.79 Hz, 1H) 8.24 (br s, 3H) 11.00 (brs, 1H). MS (ESI) m/z 274 [M+1]⁺.

Step 5: Synthesis of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide

To a jacketed 3-neck round bottom flask was charged L (55 g),2-(4-chlorophenyl)-2,2-difluoroacetic acid (33.8 g), DMF (495 mL), andN-methylmorpholine (49.6 mL). 1-Propylphosphonic anhydride (174 mL as a50 wt % solution in DMF) was then charged to the slurry keeping theinternal temperature below 40° C. Upon complete addition, heat thereaction mixture between 35-40° C. for no less than 12 hours. AdditionalDMF (27.5 mL) was added followed by water (144 mL) keeping the internaltemperature at between 15-20° C. The mixture was seeded with2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide,and held for 2 h at 20° C. Additional water (401 mL) was charged over 5h. The mixture was then filtered and the wet cake was washed with 60 wt% DMF in water (55 g), followed by water washes. The wet cake was thendried in a vacuum oven at 22° C. with a nitrogen purge to yield a whitepowder (65.5 g). Typical isolated yields were 85-95%. ¹H NMR (300 MHz,DMSO-d₆) δ ppm 2.00 (dtd, J=12.61, 5.25, 5.25, 2.21 Hz, 1H) 2.38 (qd,J=13.22, 4.43 Hz, 1H) 2.56-2.65 (m, 1H) 2.91 (ddd, J=17.47, 13.66, 5.34Hz, 1H) 4.24-4.49 (m, 4H) 5.10 (dd, J=13.28, 5.19 Hz, 1H) 7.37 (d,J=7.78 Hz, 1H) 7.40 (s, 1H) 7.58-7.64 (m, 4H) 7.68 (d, J=7.78 Hz, 1H)9.68 (t, J=6.10 Hz, 1H) 10.58 (s, 1H); MS (ESI) m/z 462 [M+1]⁺; Anal.Calcd for C₂₂H₁₈ClF₂N₃O₄: C, 57.21; H, 3.93; Cl, 7.68; F, 8.23; N, 9.10;O, 13.86. Found: C, 56.96; H, 3.80; N, 9.14.

Step 5A: Synthesis of methyl 2-(4-chlorophenyl)-2,2-difluoroacetate

To a reactor was charged methyl 2-(4-chlorophenyl)-2-oxoacetate, DCM anddiethylaminosulfur Trifluoride (DAST). The mixture was agitated at22-32° C. for 6-20 hours. At the end of the reaction, the batch wascooled to 0-10° C., and water was charged. The batch was stirred for30-60 min and layers separated. The organic layer was washed with Na₂CO₃solution once followed by water wash twice. The organic layer wasconcentrated to 1-1.5× at below 45° C. under reduced pressure. MTBE(2-3×) was then charged and residual DCM level was tested (target NMT10%). The solution was drummed to be used in the next step.

Step 5B: Synthesis of 2-(4-chlorophenyl)-2,2-difluoroacetic acid

To a reactor was charged methyl 2-(4-chlorophenyl)-2,2-difluoroacetate(E) and MTBE. Aqueous NaOH (8% w/w) was added slowly to the batch tocontrol the batch temperature at 20-30° C. The mixture was agitated at20-30° C. for 2-4 h. At the end of the reaction, the batch was split.The aqueous layer was concentrated to 2-4× Vol under vacuum at a batchtemperature of <50° C. until MeOH level was tested below or equal 0.3%.The batch was charged MTBE and cooled to 0-10° C. Concentrated HCl wasadded dropwise controlling the batch temperature below 25° C. untilbatch's pH reaches 1-2. The batch was split and organic layer was washedby water. Organic layer was concentrated under reduced vacuum under 55°C. Heptane was added and batch concentrated. Repeat adding Heptane anddistill until MTBE level in batch was less than 0.5%. More heptane wasadded and the batch was agitated at 55-65° C. for 0.5-2 h when all soliddissolve. The batch was cooled to 10-20° C. over at least 2 h and keptat this temperature for 1-3 h. The batch was filtered and dried in ovento yield compound P. Typical yield was 75-85%. ¹H NMR (400 MHz, CDCl₃) δppm 7.48 (d, J=8.4 Hz, 2H) 9.05 (broad, 1H); MS (ESI positive mode) m/z205 [M−1]⁺.

Step 6: Synthesis of Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide

To a solution of2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindoline-5-carbonitrile (25 g, 54.1mmol) in formic acid (262 mL) was added water (50 mL) and seed (0.5 g).The batch was agitated for 15 min and added water (212 mL) over 1 h. Thebatch was heated to 55 to 65° C. and agitated at 55 to 65° C. for atleast 16 h followed by cooling to 15 to 25° C. The mixture was filteredand washed with a mixture of formic acid and water (1:1 by vol, 50 mL)then twice with water (50 mL). The solid was dried under vacuum at 40°C. to give2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamideas white solid (23 g, 93% yield). ¹H NMR (300 MHz, DMSO-d₆) δ ppm1.98-2.04 (m, 1H) 2.33-2.46 (m, 1H) 2.58-2.64 (m, 1H), 2.86-2.98 (m,1H), 4.29 (d, J=18.0 Hz, 1H), 4.43 (d, J=18 Hz, 1H), 4.46 (d, J=5.4 Hz,2H), 5.12 (dd, J=4.8, 13.0 Hz, 1H), 7.37 (d, J=7.8 Hz, 1H), 7.40 (s, 1H)7.58-7.64 (s, 4H), 7.68 (d, J=7.8 Hz, 1H), 9.70 (t, J=6.0 Hz, 1H) 11.01(s, 1H); MS (ESI) m/z 462 [M+1]⁺.

Example 4 Synthesis of Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide

Compound Q (6.5 g) was added to acetone (195 ml) in a reactor. Thereactor was pressurized with nitrogen to 30-35 psig. The reactionmixture was heated to 70-75° C. with agitation. The pressure was thenadjusted with nitrogen to 50-55 psig. The mixture was agitated at 70-75°C. for minimum 24 hours, then cooled to room temperature (20-25° C.).The pressure was released and the mixture was filtered. The cake waswashed with acetone. The resulting solid was dried in oven to obtainForm C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamideas white to off-white solid (5.9 g, 90% yield). XRPD confirmed theproduct as Form C of2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.

Example 5 Synthesis of methyl4-cyano-2-(((methylsulfonyl)oxy)methyl)benzoate

Compound A (6.89 g, 32.0 mmol, 1 eq) was slurred in DMA (50 mL) at20-25° C. in a water bath and Me₂SO₄ (4.44 g, 35.2 mmol, 1.1 eq) wasadded dropwise over 20 min. The resulting slurry was aged at thistemperature for 3 h. NMM (7.04 mL, 64.0 mmol, 2 eq) was added to theslurry, followed by a slow addition of a solution of Ms₂O (6.74 g, 38.72mmol, 1.21 eq) in DMA (15 mL) over 20 min at 20-25° C. in a water bath.The reaction mixture was stirred at room temperature overnight. Waterwas added to the mixture while keeping temperature <20° C. until ahomogenous solution was obtained. More water was added until a slurryformed, which was filtered. The solid was washed with water, dissolvedin DCM and dried over Na₂SO₄. Filtration and concentration gave a crudeproduct, which was purified by CombiFlash (dry loading, eluent: 30%EtOAc in hexanes) to give Compound D (5.95 g, 69.1%) as a white solid.

The embodiments described above are intended to be merely exemplary, andthose skilled in the art will recognize, or will be able to ascertainusing no more than routine experimentation, numerous equivalents ofspecific compounds, materials, and procedures. All such equivalents areconsidered to be within the scope of the invention and are encompassedby the appended claims.

What is claimed:
 1. A process for preparing2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamidecomprising contacting Compound M with2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of a base and1-propylphosphonic anhydride in a solvent, under conditions suitable toprovide2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide,wherein Compound M is selected from methanesulfonate, hydrochloride,sulfate, phosphate and acetate salt of3-(5-(aminomethyl)-1-oxoisoindolin-2-yl)piperidine-2,6-dione.
 2. Theprocess of claim 1, wherein the process comprises contacting Compound L

with 2-(4-chlorophenyl)-2,2-difluoroacetic acid in the presence of abase and 1-propylphosphonic anhydride in a solvent, under conditionssuitable to provide2-(4-chlorophenyl)-N-((2-(2,6-dioxopiperidin-3-yl)-1-oxoisoindolin-5-yl)methyl)-2,2-difluoroacetamide.3. The process of claim 1, wherein the base is N-methyl morpholine. 4.The process of claim 1, wherein the solvent is dimethylformamide.
 5. Theprocess of claim 1 further comprising contacting Compound G

with a reducing agent in a solvent followed by contacting with an acidselected from methanesulfonic acid, hydrochloric acid, sulfuric acid,phosphoric acid, or acetic acid, under conditions suitable to provideCompound M.
 6. The process of claim 5, wherein the reducing agent is 5%or 10% palladium on carbon.
 7. The process of claim 5, wherein thesolvent comprises one or more of N-methyl pyrrolidone, 1 propanol,isopropyl alcohol, ethanol and tetrahydrofuran.
 8. The process of claim1 further comprising contacting Compound G

with a reducing agent in a solvent followed by contacting with anmethanesulfonic acid, under conditions suitable to provide Compound L.9. The process of claim 8, wherein the reducing agent comprises 10%palladium on carbon.
 10. The process of claim 8, wherein the solventcomprises water and 1-propanol.
 11. The process of claim 8, wherein thesolvent comprises water and isopropanol.
 12. The process of claim 8further comprising contacting Compound X

wherein L¹ is a leaving group; with 3-aminopiperidine-2,6-dionehydrochloride in the presence of a salt, followed by a solvent and abase, under conditions suitable to provide Compound G.
 13. The processof claim 12, wherein L¹ is halogen or methanesulfonate.
 14. The processof claim 8 further comprising contacting Compound D

with 3-aminopiperidine-2,6-dione hydrochloride in the presence of asalt, followed by a solvent and a base, under conditions suitable toprovide Compound G.
 15. The process of claim 12, wherein the salt ispotassium bromide or potassium iodide.
 16. The process of claim 12,wherein the base is N,N-diisopropylethylamine.
 17. The process of claim12, wherein the solvent comprises acetonitrile.
 18. The process of claim12, wherein the solvent comprises acetonitrile and water.
 19. Theprocess of claim 12 further comprising contacting Compound A

with 1) dimethyl sulfate in a solvent; 2) a base; 2) methanesulfonylchloride; and 4) lithium chloride, under conditions suitable to provideCompound D.
 20. The process of claim 14, wherein the base is N-methylmorpholine.
 21. The process of claim 14, wherein the solvent isdimethylacetamide.
 22. The process of claim 19 further comprisingcontacting 1-oxo-1,3-dihydroisobenzofuran-5-carbonitrile

with a base in a solvent under conditions suitable to provide CompoundA.
 23. The process of claim 22, wherein the base is potassium hydroxide.24. The process of claim 22, wherein the solvent is isopropyl alcohol.